1. Field of the Invention
The present invention relates to a human parainfluenza virus type 4A (PIV-4A) fusion protein (F protein), a gene coding for the same and its application.
2. Background Art
In order to enhance a therapeutic effect of a virus infectious disease, it is necessary to identify the infection virus and to conduct a proper treatment based on the results of the identification.
In general, virus has hitherto been identified based on serological properties. Typical examples of such a method known in the art include enzyme-linked immunosorbent assay (ELISA), neutralization reaction method, complement fixation reaction, hemagglutination inhibition reaction, fluorescent antibody technique and agar precipitation reaction. In all the above-described methods, the presence or absence of a virus is determined through the determination of an antibody to the virus in a sample. Therefore, in order to determine the presence or absence of a virus with a high accuracy, the determination of the antibody should have been generally conducted about one week after the infection at a stage in which the virus antibody titer begins to increase. In some cases, redetermination for identification should have been conducted several weeks after the first determination. Thus, the prior art methods had a problem that it is difficult to conduct the diagnosis before onset of a viral disease or at an early stage of the onset of a viral disease.
ELISA is generally used for the determination of PIV-4A. In this method, an antibody to PIV-4A is determined. For example, the determination is conducted by adding a sample to a plate having PIV-4A immobilized thereon, allowing a reaction to proceed, washing the sample, further adding an anti-PIV-4A antibody, allowing a reaction to proceed and developing a color. In this method as well, it is difficult to conduct the diagnosis before onset of a viral disease or at an early stage of the onset of a viral disease, so that the initiation of the treatment is delayed, which unfavorably makes it difficult to enhance the therapeutic effect.